I'm not sure which states do, but some counties here in California do not require smog, but this may be changing. The cat is not a problem anymore, they can be had new for about 60 bucks from most aftermarket shops (summit, jegs, etc) it is the issue of passing the emission test is often more a problem. One thing to note is that California is a 'trend' setter for the most stringent smog laws and most states eventually follow. I know in Oregon they plug into the OBDII port to do a scan and make sure things are cool and no computer faults are detected. You can hit each states DMV and get info from them on the rules. Remember "It is a FEDERAL OFFENCE to tamper with, disable, or destroy any lavatory smoke detector"...er I mean smog equipment. Also some states have exemptions based on cost of repair if the car has stock equipment. For working around the system...hmm, plenty of ways but that might be wrong...

Emissions testing varies from State to State. Actually, county to county. Some states require testing, some only require testing on newer cars and some don't test at all. Louisiana, Maine, New Hampshire, Upstate New York, North Carolina and Vermont test only 1996 and newer cars. Missouri, which requires tests in the St. Louis area, planned to stop testing vehicles older than '96 models last fall. Wisconsin is debating whether to end testing of pre-1996 model cars in seven counties that now require it. I believe Florida, South Dakota, Kansas, Hawaii, Ohio, Dallas/Fort Worth, Nebraska and most of Arizona don't require testing at all. Of course, these rules change all the time, so your best bet is to check with local laws.